Plural of Axis: Understanding the Correct Form and Usage
Quick Answer
The plural of axis is axes. The word “axises” is not correct in English.
One: The Earth spins on its axis.
More than one: A graph has two axes — the x and the y.
Axis Becomes Axes — See the Pattern
Look at these words. Can you see what happens?
- one axis → two axes
- one crisis → two crises
- one basis → two bases
- one analysis → two analyses
Did you see the pattern? The -is at the end changes to -es. This rule works for many English words that come from Greek.
| One (singular) | More than one (plural) |
|---|---|
| axis | axes |
| crisis | crises |
| basis | bases |
| analysis | analyses |
| thesis | theses |
Why It Is Axes and Not Axises
Most English plurals just add -s or -es to the end of the word: cat → cats, box → boxes. But the word axis comes from Greek. Greek words that end in -is follow a special rule. The -is changes to -es:
- axis → axes (not “axises”)
- crisis → crises (not “crisises”)
- basis → bases (not “basises”)
An axis is an imaginary line that something turns around or is built on. The Earth has an axis. A graph has two axes. You say it like “AK-sis” for one, and “AK-seez” for more than one.
Easy way to remember: Think of crisis → crises. Most people know that one. The word axis works the same way: axis → axes.
The Rule in One Line: Axis ends in -is, so the plural is axes (-is → -es).
How to Use Axis and Axes in Everyday English
- The Earth turns on its axis once every 24 hours. (one axis)
- Every graph in maths has two axes: the x and the y. (more than one)
- The planet’s axis is tilted, and that is why we have seasons. (one axis)
- This 3D printer can move on three axes at the same time. (more than one)
- The wheel spins around a metal axis in the middle. (one axis)
You are doing great. Now let us look at the mistakes most learners make with this word.
The Most Common Mistakes With Axis
Many learners write “axises” because most English plurals just add -s or -es. That is a smart guess — but it does not work for words from Greek. Even native speakers’ children make this mistake when they are learning to talk. So if you get confused, you are not alone.
✗ The graph has two axises.
✓ The graph has two axes.
✗ The Earth spins on its axe.
✓ The Earth spins on its axis.
✗ All three axises are equal in length.
✓ All three axes are equal in length.
How to remember: The word ends in -is. If you see -is at the end, change it to -es. Axis → axes. Simple.
One small thing to watch out for: the word axes is also the plural of axe (the tool for chopping wood). The spelling is the same, but the sound is different. Axes (lines) sounds like “AK-seez”. Axes (tools) sounds like “AK-siz”. Don’t worry — the sentence around it will always make the meaning clear.
Other words like this: crisis → crises, basis → bases, analysis → analyses, thesis → theses, hypothesis → hypotheses.
Test Yourself: Axis or Axes?
Choose the correct answer for each sentence. Click Check to see if you are right.
1. The Earth spins on its _______ once every day.
2. A normal graph has two _______: the x and the y.
3. Our planet is tilted on its _______, and that gives us seasons.
4. This robot can move along three different _______ at once.
5. The diagram shows four _______ meeting at one point.
Keep Going — You Are Building Something
You just learned that axis becomes axes. That is one more plural you will never get wrong again.
But here is something interesting. The word crisis follows the same rule — but most people get it wrong in spoken English. Do you say “crisises” when something bad happens many times? And what is the difference between “a crisis” and “crises” in real life?
Next lesson: What Is the Plural of Crisis?
Sources
Definition of axis — Cambridge Dictionary
My name is Khamis Maiouf. I am the creator of the English Teacher Site, dedicated to providing valuable resources and insights for students around the world. With a passion for education and a commitment to helping students enhance their skills, I aim to make English teaching more effective and enjoyable for both educators and students.
